High potential equalizer for standoff insulators



J. F. FRESE 2,469,380

HIGH POTENTIAL EQUALIZER FOR STANDOFF INSULATORS May l0, 1949.

Original Filed March 1, 1944 [kill/111,11

Patented May 10, 1'949 HIGH POTENTIAL EQUALIYZER FOR STANDOFF INSULATORS Joseph F. Frese, Baltimore, Md., assigner to Monitor Controller Company, Baltimore, Md., a corporation of Maryland original application March 1, 1944, serial No. 524,594, now Patent No. 2,399,430. Divided and this application October 20, 1944, Serial No.

4 claims. 1

My invention relates broadly to high frequency electrical apparatus and more particularly to a construction of high frequency potential equalizer for association wih stand-off insulators in high frequency electrical systems.

This application in a division of my application Serial Number 524,594, led March 1, 1944, for High frequency electrical switch and contactor system now Patent 2,399,430, dated April 30, 1946.

One of the objects of my invention is to provide an improved construction of corona shield for high potential, high frequency electrical apparatus.

Another object of my invention is to provide a construction of high potential, high frequency terminal unit for association with stand-off insulators in high frequency systems for reducing discharge losses to a minimum.

Still another object of my invention is to provide an improved construction of high potential surface equalizer for association with stand-off insulators in high frequency systems for reducing brush discharge losses to a minimum.

A further object of my invention is to provide an improved construction of streamlined high potential, high frequency unit for improving electrical eiIiciency in high frequency, high potential circuits by maintaining discharge losses at circuit connection or terminal positions at a minimum.

Other and further objects of my invention reside in an improved construction of substantially toroidal shaped high frequency unit which may be produced on a quantity production 'basis at relatively low cost embodying structural features of novelty set forth more fully in the specication hereinafter following by reference to the accompanying drawings, in which:

Figure l is a side elevational view of the potential equalizer of my invention mounted in position upon a stand-olf insulator with parts broken away and shown in section; Fig. 2 is a plan view of the potential equalizer illustrated in Fig. 1 with parts partially broken away and shown in section; and Fig. 3 is a transverse sectional View through the parts of the potential equalizer showing the manner in which the parts are assembled for forming the potential equalizing surface.

Referring to the drawings in detail, I have shown my invention applied to a stand-oil insulator by which conduits or electrical connectors shown at 4U, 4|, 42 and 43 are interconnected. Set screws 40a, 4Ia, 42a and 43a extend through one or the other of the potential equalizing symmetrical shells 44 and 45 for clamping the tubes or electrical connectors 40, 4I, 42 and 43 in 2 position. It will be observed that the sections 44 and 45 are each symmetrical, (except that section 44 is in the nature of a cap having a closed end 44a forming a socket 44h into which the endV o1' stand-off insulator projects after passing through aperture 45a in section 45).

The coacting sections 44 and 45 are modied from true toroidal shape and are substantially square with corners formed on radii that will substantially reduce discharge losses. Coacting sections 44 and 45 are brazed or welded together, edge to edge, to form the equalizing surface. Bolt member 46 which passes through aligned apertures 40e, 40f' and 42e and 42d in the internal end walls in the diametrically opposite sockets, 40h and 42h formed between thel coacting members 44 and 45 serves to secure the potential equalizing device adjacent the end of the stand-off insulator.

In Fig. 3, I have shown the two parts of the potential equalizer, the connectors, and the securing screws assembled in spaced positions, preparatory to being secured together for completing the corona shield.

I have shown connecting means for four electrical connectors but it will be understood that the stand-off insulator may be employed for connection of but two electrical connectors in which event socket portions are omitted from the structure of the shells constituting the potential equalizing device.

The structure of the corona shield is such that substantial Weight is saved, thereby making the structure useful as a stand-oil insulator without increasing mechanical supporting diiilculties in an assembly requiring a number of these units in relatively close proximity. I have conducted various stand-oir insulator tests where visible and audible corona discharge started at 89 kv. R. M. S. cycles and actual flash-over occurred at 93 kv. R. M. S. 60 cycles. Accordingly, it will be seen that the structure of my invention provides very substantial protection as a stand-off insulator device.

While I have described my invention in certain of its preferred embodiments, I desire that it be understood that modifications may be made and no limitations upon my invention are intended other than may be imposed by the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is as follows:

1. A potential equalizing surface device comprising a pair of substantially hollow shell-like metallic members electrically and mechanically connected edge to edge to form a substantially uninterrupted continuous surface, in symmetrical arrangement, and internal connecting means formed in opposite ends of said members for establishing an electrical circuit through said device, conncctoi's projecting into said internal connecting means, and screw means extending through and wholly conned within one of said members and engaging said connectors for se-A curing said connectors in interlocked relations.

2. A potential equalizing surface device comprising a pair of shell-like metallic members mechanicallyland electrically connected edge to edge for forming a substantially stream-lined continuous equi-potential surface, diametrically extending semi-cylindrical sockets formed in opposite ends of said members and mutually aligned to form substantially cylindrical sockets, electrical circuit terminals extending into said sockets, and adjustable screw means extending through and wholly confined within one of said members and adjustable through the socket therein and engageable with the electrical circuit terminals for securing said electrical circuit terminals within said sockets.

3. A potential equalizing device comprising a corona shield consisting of a pair of coacting substantially hollow members mechanically and electrically connected edge to edge and forming a substantially stream-lined equi-potential surface, each of said members having rounded external surfaces and having dametrically extending symmetrically disposed cylindrical sockets therein, electrical connectors extending into said sockets, and adjustable screw means passing through one of said members and wholly confined within the limits oi the external surface thereof and individual to each of said sockets for engaging said electrical connectors and securing said electrical connectors in position with respect to said corona shield.

4. A potential equalizing device comprising a corona shield consisting of a pair of substantially hollow coacting conductive members mechanically and electrically connected edge to edge and forming a substantially uninterrupted continuous equi-potential surface, each of said members having rounded external surfaces and having diametrically extending symmetrically disposed cylindrical sockets therein, electrical connectors extending into said sockets, and means passing through one of said members and wholly contlned within the limits of the external surface thereof and into the socket therein for gripping the electrical connector extending into the socket for securing said electrical connectors in position with respect to said corona shield, said rounded external surfaces having radii not less than approximately %th of an inch for voltages in the range of 80,000.

JOSEPH F. F'RESE.

REFERENCES CITED The following referencesare of record in the file. of this patent:

UNITED STATES PATENTS Number Name Date Re. 17,828 Stanton et ai Oct. 14, 1930 Re. 18,773 Thomas Mar. 21, 1933 789,433 King May 9, 1905 842,942 Clark L Feb. 5, 1907 1,010,181 Sandford, Jr Nov. 28, 1911 1,730,250 Smith Oct. 1, 1929 1,899,309 Buchanan Feb. 28, 1933 1,934,581 Bach Nov. 7, 1933 1,997,627 Casey Apr. 16, 1935 FOREIGN PATENTS Number Country Date 70,492 Sweden Oct. 28, 1930 

